Electrostatic discharge is a phenomenon in which electrostatic charge flows into a semiconductor integrated circuit from an external source. In semiconductor applications, the electrostatic discharge can destroy the integrated circuit. For example, when the electrostatic discharge phenomenon occurs, an amount of electrostatic charge flows into or out of a semiconductor integrated circuit in a moment, resulting in an excessive current flow through the semiconductor integrated circuit device. In this situation, an excessive voltage flows through an internal circuit resulting in, for example, junction breakdown, line melting, oxide film dielectric breakdown, or the like, thereby destroying the semiconductor integrated circuit.
In order to prevent the semiconductor integrated circuit from breaking due to the electrostatic discharge phenomenon, an electrostatic discharge (ESD) device is commonly provided between an external terminal and an internal circuit of a semiconductor integrated circuit. The ESD device forms a bypass for the excessive current, thereby protecting the integrated circuit. There are many different types of ESD devices commonly employed, including current limiting elements for limiting a transient current flowing in a semiconductor integrated circuit, such as a diffused resistor and a polysilicon resistor. However, ESD devices are challenged for SOI finFET devices since Si thickness of the finFET devices cannot be increased as it competes with the process window of the replacement metal gate (RMG) flow.